UPDATE: Yep, the cat was plugged up and the exhaust hardware put up as much fight as expected. Three of the nuts came off with the help of penetrating oil and an impact gun. One nut (the front one inside the pipe elbow) wouldn't budge and got rounded off. After giving it some thought and being already EXHAUSTED, I went to a nearby Lowe's to buy and angle grinder with a metal cut off disk. Since the rear flange was separated, I moved the resonator back and flexed the cat down to make more room for cutting. Not a fun job if you don't have a lift, but a shop was charging $800 for the same.

I gutted it to put the pipe back in, but not much luck with the noise since one of the studs had to be cut. But enough to test drive the vehicle and verify that the engine runs okay and the tranny is shifting properly. Going to put in the replacement cat next week when that arrives. About $300 with the tax and shipping on Cali.

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So I'm helping my dad with his car troubles lately (02 Maxima and an 05 Altima).


We spent the better half of the day fighting with the bad alternator on Saturday. Not a very fun location or fastener placement.


Got that done but a new problem has occurred. Severe loss of power, occasional stalling, and ugly rattling noises when you do floor the pedal. Plus an awful lot of heat coming off from the bottom and the engine bay in the short time of the test drive. The vehicle is a daily driver but was parked for about a week and a half due to alternator issues.


Apart from rattles, when you put it in P and mash the gas, the flex coupling a couple feet in front of the rear cat stretches noticeably. About a full 2" give or take. Not sure if that's normal for these Maximas (our is a Cali emissions version), but my bet is on the plugged cat creating an awful lot of exhaust back pressure. Of course, my dad has a bunch of coworkers suggesting random parts to replace first lol. No codes pending or stored when we test drove it around the block a few times.


Is that sort of visible movement in the exhaust normal for this gen Maximas when you stomp the gas for a split second? Because everything points to a major exhaust obstruction so far.


I'm fixing to unbolt the rear cat to inspect it. If plugged, gut it! Not exactly an EPA approved repair procedure, but that motor might be clapped anyway between the oil burning and my dad, bless his heart, figuring there's no need for oil changes when you have add a quart every two or three tanks of gas anyway.


Just NOT looking forward to fighting old rusty exhaust hardware without a lift.

Cat completely plugged up, view from the exhaust-in side.

Rear looks better, but only a few pinholes worth of light seen looking at the sun. TOTALLY safe for continuously looking at the sun or eclipse, LOL.

Not exactly an EPA or CARB approved repair, but it'll do until the new cat arrives mid next week along with the gaskets and replacement hardware.

 

Suggest getting an aftermarket cat rather than gutting it.

 

I hear ya. It's just that Altima needs repairs too and has a LOT less mileage than the 225k on the Maxima. And that motor may well be clapped beyond repair at this point. Certain folks think that adding a quart of oil every other tank of gas makes oil changes "unnecessary". Oil may be burning or leaking, but the sludge stays where it's at.

 

My son drives a 2003 I35 with 128K and she burns about a QT in 700 miles, no leaks, no smoke, no CEL, no drivability issues. It has new PCV valve and ADDW1 inline catch can. The oil DOES get very black and sludgy.

 

I own a 2003 I35 with 185,000 miles and I have the exact same issues - burning oil and oil turning dark. Other than that a couple of oil leaks but it has no other issues.